1. Field of the Invention
This invention relates to apparatus for closing filled sacks, preferably large sacks, which consist at least in part of thermoplastic material, comprising a feeder for feeding the filled sacks into a closing station, which feeder preferably comprises a roller conveyor, or a belt conveyor also comprising means for holding the top end portion of the sack above the contents of the sack, pressure-applying bars, which are parallel to each other and adapted to be lowered onto the contents of the sack on both sides of the sack end portion, which is held taut, which pressure-applying bars when in a lower position define between them a gap for the passage of the sack between said bars, and closing means provided above the pressure-applying bars.
2. Description of the Prior Art
Apparatus of that kind has been disclosed in German Patent Publication No. 12 65 643 and comprises a channel-shaped folding rail, which is linked by levers to links which carry one of the pressure-applying bars. When the sack end portion has been released by the expanding means, that rail is pivotally movable over the sack end portion by means of a fluid-operable piston-cylinder unit so as to reversely fold that sack end on itself and when the belt conveyor is restarted said folded sack end portion is introduced into track rails and is fed along said track rails to a sewing machine for fixing the sack end portion in its reversely folded position.
Particularly large sacks which have been filled are desired to be closed at their top end by means of a seam weld by which said top end is also secured to the sack.